Borderline hyperprolactinemia in infertile women: evaluation of the prolactin response to thyrotropin releasing hormone and double-blind placebo-controlled treatment with bromocriptine

Twenty-two women with on average more than 3 years unexplained infertility including normal menstrual cycles were studied because of borderline hyperprolactinemia (repeated serum prolactin concentrations 400-1000 mU/l). Randomized double-blind treatment with bromocriptine 5 mg daily (leading to adequate prolactin suppression) or matching placebo, each for 4 cycles, resulted in a cumulative rate after 4 months of 14.3 +/- 10.6% (SE) in both groups. Also, the results of treatment were not significantly related to the serum prolactin response to an intravenous injection of thyrotropin releasing hormone, whether the response was blunted (ratio of peak to basal prolactin within 60 minutes of injection no greater than 2), intermediate (greater than 2 to 4) or normal (greater than 4).